On Sun, Nov 8, 2015 at 11:38 PM, <[email protected]> wrote: > >Why would you need to turn them into Seqs for that? > Because....that's just the way I did it and it seems to be working. I find > it useful because it meets my business requirement. I'm not saying it's *the > answer*, I'm just seeking a code critique and advice from any of you much > smarter people who have a little time to spare :) >
:-) > > This is basically what I do: > > type TimeSeriesPoint = (DateTime, Int) > > val timeSeriesSources: List[Source[TimeSeriesPoint, Unit]] = ??? > > def total(points: immutable.Seq[TimeSeriesPoint]): TimeSeriesPoint = > points.reduce((point1, point2) => (point1._1, point1._2 + point2._2)) > > StreamUtils.sequencedSource(timeSeriesSources).map(total) > > > Source.reduce? > >Because Sources are not bounded in nature. > Ah, yes. Good point. I only use this on Sources of time series data we've > queried from the database. So we're only using it on bounded sources by > convention; is there a type that represents a bounded source? That might be > useful. > I'm not convinced it would be feasible to encode—just imagine all the permutations of all transformations. Is a bounded source a subtype of an unbounded or vice versa? > > On Sunday, November 8, 2015 at 5:15:04 PM UTC-5, √ wrote: > >> >> >> On Sun, Nov 8, 2015 at 10:57 PM, <[email protected]> wrote: >> >>> > That sounds like a feature of questionable value >>> I have multiple sources of time series data. Each source is over the >>> same time range and I'd like to aggregate them into one time series. So I >>> use this method then on each of the resulting source's sequences I map it >>> into the sum or average of all those points. >>> >>> I'm genuinely curious if there's a better way to do it. >>> >> >> Why would you need to turn them into Seqs for that? >> >> >>> >>> >>> > it's very easy to arrive at OOMEs with such a method. >>> How so? >>> >> >> Because Sources are not bounded in nature. >> >> >>> >>> >>> On Sunday, November 8, 2015 at 3:27:35 PM UTC-5, √ wrote: >>>> >>>> That sounds like a feature of questionable value, it's very easy to >>>> arrive at OOMEs with such a method. >>>> >>>> On Sun, Nov 8, 2015 at 9:24 PM, <[email protected]> wrote: >>>> >>>>> I wasn't very clear in my original requirements. In the resulting >>>>> Source, I want its 1st element (i.e. its 1st sequence) to contain all the >>>>> 1st elements of the input sources; its 2nd sequence to contain all the 2nd >>>>> elements of the input sources; and so on until the shortest input source >>>>> ends. >>>>> >>>>> It's slipping my mind if this functionality has an analogue in the >>>>> standard library or I'm mislabeling it. >>>>> >>>>> I hope this clarifies what I'm talking about. >>>>> >>>>> >>>>> On Sunday, November 8, 2015 at 2:31:28 PM UTC-5, Giovanni Alberto >>>>> Caporaletti wrote: >>>>>> >>>>>> Why not just something like the following? >>>>>> >>>>>> val seqOfSources: Seq[Source[Int, Unit]] = Seq(List(1,2), List(3,4), >>>>>> List(5,6)).map(Source(_)) >>>>>> >>>>>> val sourceOfSeqs: Source[Seq[Int], Unit] = >>>>>> Source(seqOfSources.toList).flatMapConcat(identity).grouped(100) >>>>>> >>>>>> >>>>>> On Sunday, 8 November 2015 19:26:56 UTC+1, [email protected] wrote: >>>>>>> >>>>>>> Hello, >>>>>>> >>>>>>> I've been working on a way to turn a *Seq[Source[T]]* into >>>>>>> *Source[Seq[T]]* using Akka Streams 2.0. I believe I've succeeded, >>>>>>> but I'd like people to critique my code. Thanks in advance. >>>>>>> >>>>>>> object StreamUtils { >>>>>>> >>>>>>> def sequencedSource[T](sources: immutable.Seq[Source[T, Unit]]): >>>>>>> Source[immutable.Seq[T], Unit] = >>>>>>> Source.fromGraph(FlowGraph.create() { implicit builder => >>>>>>> import FlowGraph.Implicits._ >>>>>>> >>>>>>> val sequenceGraphStage = builder.add(new >>>>>>> SequenceGraphStage[T](sources.size)) >>>>>>> for ((source, index) <- sources.zipWithIndex) source ~> >>>>>>> sequenceGraphStage.in(index) >>>>>>> >>>>>>> SourceShape(sequenceGraphStage.out) >>>>>>> }) >>>>>>> >>>>>>> } >>>>>>> >>>>>>> class SequenceGraphStage[T](numInputs: Int) extends >>>>>>> GraphStage[UniformFanInShape[T, immutable.Seq[T]]] { >>>>>>> >>>>>>> require(numInputs > 0, "1 or more inputs required") >>>>>>> >>>>>>> val inputs = immutable.IndexedSeq.tabulate(numInputs)(num => >>>>>>> Inlet[T]("Sequence.in" + num)) >>>>>>> val output = Outlet[immutable.Seq[T]]("Sequence.out") >>>>>>> >>>>>>> override val shape = UniformFanInShape(output, inputs: _*) >>>>>>> >>>>>>> override def createLogic(inheritedAttributes: Attributes): >>>>>>> GraphStageLogic = new GraphStageLogic(shape) { >>>>>>> val elements = mutable.Buffer.empty[T] >>>>>>> >>>>>>> setHandler(output, new OutHandler { >>>>>>> override def onPull(): Unit = >>>>>>> inputs.foreach { input => >>>>>>> read(input) { element => >>>>>>> elements += element >>>>>>> >>>>>>> if (elements.size == inputs.size) { >>>>>>> push(output, elements.to[immutable.Seq]) >>>>>>> elements.clear() >>>>>>> } >>>>>>> } >>>>>>> } >>>>>>> }) >>>>>>> >>>>>>> inputs.foreach(setHandler(_, eagerTerminateInput)) >>>>>>> } >>>>>>> >>>>>>> override val toString = "Sequence" >>>>>>> >>>>>>> } >>>>>>> >>>>>>> >>>>>>> BTW, I did something similar in Streams 1.0 using FlexiMerge; the >>>>>>> API and boilerplate necessary was somewhat off-putting. I greatly >>>>>>> appreciate the cleanup in 2.0 so far. >>>>>>> >>>>>> -- >>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>> >>>>>>>>>> Check the FAQ: >>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>> >>>>>>>>>> Search the archives: >>>>> https://groups.google.com/group/akka-user >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Akka User List" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> To post to this group, send email to [email protected]. >>>>> Visit this group at http://groups.google.com/group/akka-user. >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> >>>> >>>> -- >>>> Cheers, >>>> √ >>>> >>> -- >>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>> >>>>>>>>>> Check the FAQ: >>> http://doc.akka.io/docs/akka/current/additional/faq.html >>> >>>>>>>>>> Search the archives: >>> https://groups.google.com/group/akka-user >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "Akka User List" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/akka-user. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> Cheers, >> √ >> > -- > >>>>>>>>>> Read the docs: http://akka.io/docs/ > >>>>>>>>>> Check the FAQ: > http://doc.akka.io/docs/akka/current/additional/faq.html > >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user > --- > You received this message because you are subscribed to the Google Groups > "Akka User List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. > -- Cheers, √ -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
